Dificultades y limitaciones del estudio

2.1 General. The Contractor shall establish and maintain quality control for all operations to assure compliance with contract requirements and main-tain records of his quality control for all construction operations, including but not limited to the following:

(1) Material

(2) Storing and handling

(3) Placing (location, alignment, etc.) (4) Driving and splicing

(5) Cutting

2.2 Reporting. The original and two copies of these records and tests, as well as corrective action taken, shall be furnished to the Government daily. Format of the report shall be as prescribed in SP-16.

3. APPLICABLE PUBLICATIONS. The following publications of the issues listed below, but referred to thereafter by basic designation only, form a part of this specification to the extent indicated by the references thereto:

3.1 American Society for Testing and Materials (ASTM) Standards.

A 36-77a Structural Steel

3.2 American Institute of Steel Construction (AISC).

Manual of Steel Construction, 9th Edition 4. SUBMITTALS.

4.1 Equipment Descriptions. The Contractor shall submit complete de-scriptions of pile driving equipment, including hammers, extractors, and other appurtenances to the Contracting Officer for approval 45 days prior to com-mencement of work.

4.2 Handling and Storage Plans. Proposed methods of handling and stock-piling the piles shall comply with requirements of 2I-6.4 and 2I-6.5 and shall be submitted in detail to the Contracting Officer for review and approval at least 45 days prior to delivery of the production piles to the job site.

and shall be submitted in detail to the Contracting Officer for review and approval at least 45 days prior to driving the first production pile. De-scription of the alinement controls shall include the proposed methods of con-trolling the pile batter, the vertical plumbness, and rotation of the pile about the longitudinal centerline of the web.

4.4 Driving Record. The Contractor shall furnish daily to the Contract-ing Officer a copy of all drivContract-ing data required in 2I-6.7.1. Unusual driving conditions, interruptions or delays during driving, and any other information associated with the pile driving operations shall be noted. The records shall be submitted in triplicate (original and two copies).

PART 2 - PRODUCTS 5. MATERIALS.

5.1 Steel. Steel for H-piles and splice plates shall conform to the re-quirements of ASTM A 36.

5.2 Steel H-Piles. Steel H-piles shall be of the shape and sections shown on the drawings. Piles shall have standard square ends, unless other-wise specified or directed. Lengths of piles shall be determined as specified below in 2I-6.3.1.

5.3 Pile Points. Pile points shall be Pruyn H-Pile Points, Type BP-75750, or approved equal.

5.4 Steel H-Pile Splices. Pile splice plates shall conform to details shown on the drawings. All welding shall be performed by certified welders as specified in SECTION 5E. The Government will test select splices by nonde-structive methods.

5.5 Pile Tension Anchors. Pile tension anchors shall conform to details shown on the drawings. The Government will test the capacity of select ten-sion anchors.

PART 3 - EXECUTION 6. INSTALLATION.

6.1 Pile Driving Equipment. Pile driving hammers shall be steam, air or diesel operated impact, single-acting, double-acting or differential acting type. Vibratory hammers will be allowed provided applicable requirements of SECTION 2K are satisfied. The production piles shall be driven with the same size and type hammer, operating with the same effective energy and efficiency as used in driving the steel test piles (which are covered in SECTION 2K).

All pile driving equipment and appurtenant items shall be equal to that used in the test pile driving operations. The size or capacity of hammers shall be as recommended by the manufacturer for the pile weights and soil formation to be penetrated. Impact hammers shall have a minimum energy of 24,000 ft-lb for 14-inch H-piles and 19,500 ft-lb for 12-inch H-piles. The hammers shall be operated at all times at the speed and conditions recommended by the manu-facturer. Boiler, compressor, or engine capacity shall be sufficient to

operate the hammer continuously at full rated speed and inlet pressures. Once the actual driving has begun, all conditions (such as alinement, batter,

cushions, etc.) shall be kept as constant as possible. Hammers shall have firmly supported leads extending to the lowest point the hammer must reach.

In order to reduce the unbraced length of the pile during driving, the

Contractor shall provide intermediate support for the pile in the leads at no additional cost to the Government. The Contractor shall submit details on intermediate supports to the Contracting Officer for approval.

6.2 Test Piles. All work associated with the required pile tests is covered in SECTION 2K.

6.3 Permanent Production Piles.

6.3.1 Lengths. The estimated quantities of piles listed in the unit price schedule are given for bidding purposes only. The Contractor shall not order piling until he receives a quantities list from the Contracting Officer as specified below. The Contracting Officer will determine the actual lengths of production piles required to be driven below cut-off elevation for the various locations in the work and will furnish the Contractor a quantities list which indicates lengths and locations of all piles to be placed. This determination will be made from the results of the pile driving and load tests performed as specified in SECTION 2K of this specification and will be pro-vided to the Contractor as specified in SECTION 2K. Piling shall be furnished full length. Splicing of piling to make up the required lengths will not be permitted. The Contractor’s schedule shall be established to assure timely accomplishment of the pile tests, an essential item along the critical path.

6.4 Storing. Steel H-piles stored at the job site shall be stored on a level surface in an area that will not pond water and the piles shall be stacked in such a manner that all piles have uniform support along their length without sagging or bending. If it is not feasible to store the piles on a hard level surface, hardwood blocking shall be laid in such a manner so that piles are brought to level. Blocking shall be spaced at distances suf-ficiently short to prevent sagging or bending. In no case shall blocking be more than 10 feet apart nor more than 2 feet from the ends of the pile. The method of stacking shall not result in damage to the pile or excessive sweep or camber. Plan for storing H-piles shall be submitted as specified in 2I-4.2.

6.5 Handling. Pick-up points for steel H-piles shall be as shown on the drawings and shall be plainly marked on all piles. All lifting shall be done at these points. All lifting, except for lifting the pile into the driving leads, shall be accomplished using a two point pick-up. A one point pick-up may be used for lifting the pile into the driving leads. Pick-up devices shall be of the type that clamp to both pile flanges at each pick-up point.

Use of alternate types of pick-up devices shall be subject to approval by the Contracting Officer. Burning holes in flanges or webs for handling shall not be permitted. During on-site transporting of piles, the piles shall be main-tained in a straight position and shall be supported, as a minimum, at the quarter points. Dragging of piles across the ground shall not be permitted.

Before the piles are transported from the stockpile area to the driving area, all piles shall be inspected for damage and excessive sweep and camber in accordance with these specifications and the drawings. The web and flanges of the piles shall be checked by rotating the pile with the pile resting on a

A pile which is damaged and which in the opinion of the Contracting Officer is unusable, will be rejected, and shall not be transported to the driving areas.

After the piles are delivered to the driving area, they shall be checked again, visually, to insure that damage has not occurred during handling and transporting from the stockpile area to the driving area. Any pile which is damaged and which damage, in the opinion of the Contracting Officer, renders the pile unusable and/or which contains excessive sweep or camber, as defined above, shall be replaced by a new pile at no additional cost to the Govern-ment. Proposed methods of handling shall be submitted as specified in 2I-4.2.

6.6 Placement. Piles shall be accurately placed in the correct location and alinements, both laterally and longitudinally and to the vertical or batter lines as shown on the contract drawings. To insure correct placement of piles, the Contractor shall establish a rectangular grid system by use of a surveying instrument having at least the accuracy of a one-second Theodolite.

The Contractor shall check each pile, prior to driving and with the pile head seated in the hammer, for correct batter, vertical plumbness, and rotation of the pile about the centerline of the web. The vertical plumbness of the pile shall be checked with a surveying instrument having at least the accuracy of a one-second Theodolite to insure that the pile is being driven parallel to the grid line in the direction of the pile batter. A lateral deviation from the correct location at the cut-off elevation of not more than 3 inches will be permitted. A vertical deviation from the correct cut-off elevations shown on the drawings of not more than +2 inches will be permitted. A variation in alinement of not more than 1/4-inch per foot of longitudinal axis will be permitted. Moving the pile by rotating the leads, pulling on the pile, and wedging the pile will not be allowed. If, during driving, the pile shifts or otherwise moves beyond the specified tolerances, the Contractor may be re-quired to pull and redrive the pile as directed by the Contracting Officer.

Piles which are misplaced shall be pulled and redriven at no additional cost to the Government. Any voids that remain after pulling misplaced piles shall be filled with sand, and all costs related thereto shall be borne by the Contractor.

6.7 Pile Driving.

6.7.1 Driving. No piling shall be driven within 100 feet of any concrete structure, unless authorized by the Contracting Officer. A complete and

accurate record of the driving of piles as specified in 2I-4.4 shall be com-piled by the Contractor for submission to the Contracting Officer. This record shall include pile dimensions and locations, the description of hammer used, rate of hammer operation, for impact hammers the number of blows re-quired for each foot of penetration throughout the entire length of each pile, for vibratory hammers the cumulative time of penetration at five foot inter-vals shall be recorded throughout the entire length of each pile, butt eleva-tion upon compleeleva-tion of driving and any other pertinent informaeleva-tion requested by the Contracting Officer. When driving long piles of high slenderness-ratio, special precautions shall be taken to insure against overstressing and leading away from a plumb or true position. During driving, pile driving hammers shall be operated at all times at the speed, inlet pressure, and con-ditions recommended by the hammer manufacturer. Each pile shall be driven continuously and without interruption to the minimum required depth of pene-tration. Deviation from this procedure will be permitted only for cases where interruptions due to splicing as described below or the driving is stopped by causes which reasonably could not have been anticipated. If the pile is

driven with an impact hammer to the minimum depth of penetration but the minimum penetration per blow has not been attained, the pile shall be driven deeper as necessary to attain the minimum penetration per blow. The minimum penetration per blow will be determined by the Contracting Officer upon completion of the pile tests. A pile which has not reached the minimum penetration rate per blow when the top has been driven to the cut-off eleva-tion shall be spliced as shown on the drawings and driven to a depth suffi-cient to develop the minimum penetration rate per blow. All pile splices shall be fabricated by qualified welders. For impact hammers, when the maxi-mum permissible blows of 17 blows per inch for 3 consecutive inches (single-acting) or 20 blows per inch for 3 consecutive inches (double-(single-acting) is

reached above the minimum tip elevation, the pile shall be pulled and redriven or shall be cut off and either used or abandoned, as directed by the Contract-ing Officer. For vibratory hammers, when the tip does not move more than 0.1 foot per minute, the Contractor shall immediately attempt driving of the pile with an impact type hammer conforming to 2I-6.1. If redriving is neces-sary, piles shall be redriven at a site specified by the Contracting Officer.

Piles which have been uplifted after driving shall be redriven to grade after conclusion of other driving activity in that general area. if backdriving is required an equitable adjustment in contract time and price will be made in accordance with the General Provision Clause "Changes". Jetting shall not be used to assist driving the piles. Pile points shall be installed only when directed by the Contracting Officer. Method of installation shall be as recommended by pile point manufacturer.

6.7.1.1. The Contracting Officer may require that any pile be pulled for inspection. Any pile which is damaged because of internal defects or by im-proper handling or driving or is otherwise damaged so as to impair it for its intended use, shall be removed and replaced. Piles pulled at the direction of the Contracting Officer and found to be in suitable condition shall be re-driven to the required depth at a site specified by the Contracting Officer.

Any pile that cannot be driven to the required depth because of an obstruction shall be pulled and redriven at a site specified by the Contracting Officer.

Payment for pulled piles will be made in accordance with 2I-8.3.

7. MEASUREMENT.

7.1 Steel H-Piles. Measurement for furnishing and delivering steel

H-piles will be made by the linear foot for steel H-piles acceptably delivered at the site. Steel H-piles driven with an impact hammer will be measured for payment on the basis of lengths along the axis of the pile in place below the cut-off elevation. Steel H-piles driven with a vibratory hammer will be measured for payment on the basis of pile lengths determined from the testing program for piles driven with an impact hammer, see SECTION 2K. Pile lengths will be measured to the nearest tenth of a foot.

8. PAYMENT.

8.1 Furnishing and Delivering Piles. Payment for furnishing and deliver-ing steel H-piles, at the site, will be made at the applicable contract unit prices for:

"Furnish and Deliver Steel H-Piles (HP 14 x 89)",

Payment for furnishing and delivering will be made after proper storage of the piling.

8.1.1 Driving Piles. Payment for the measured length of each pile acceptably driven will be made at the applicable contract price per linear foot for "Drive Steel H-Piles (HP 14 x 89)", "Drive Steel H-Piles

(HP 14 x 73)", and "Drive Steel H-Piles (HP 12 x 53)". These prices shall include all items incidental to driving the piles and cutting off all piles at the cut-off elevation. Payment for furnishing and installing tension anchors will be made according to SECTION 5J. No additional payment will be made for the use of an impact hammer on piles which have refused with a vibratory hammer. Payment for furnishing and driving test piles will be made according to SECTION 2K.

8.2 Reserved.

8.3 Pulled Piles.

8.3.1 Undamaged Pile. Piles which are pulled at the direction of the Contracting Officer and found to be in good condition will be paid for at the applicable contract unit price for "Furnish and Deliver Steel H-Piles" and

"Drive Steel H-Piles" in its original driven position. The cost of pulling and backfilling with sand, if applicable, will be paid for at the applicable contract unit price for "Drive Steel H-Piles". Such pulled piles when re-driven will be paid for at the applicable contract unit price for "Drive Steel H-Piles".

8.3.2 Damaged Pile. Where a pile is pulled and found to be defective and or damaged due to Contractor negligence or internal defects, no payment will be made for either originally furnishing and driving such pile or for the operation of pulling and backfilling with sand, if applicable, and it shall be replaced by a new pile which will be paid for at the applicable contract unit prices. Piles which are pulled and found to be damaged through no fault of the Contractor will be paid for the applicable contract unit price for

"Furnish and Deliver Steel H-Piles" and "Drive Steel H-Piles" in its origi-nally driven position. The cost of pulling and backfilling with sand, if applicable, will be paid for at the applicable contract unit price for "Drive Steel H-Pile". A new pile shall be driven in place of the defective and/or damaged pile and will be paid for at the applicable contract unit prices.

8.4 Steel H-Pile Splices. For each pile splice directed by the Contract-ing Officer, payment will be made at the rate of $200 per splice. This price shall include the cost of furnishing all plant, labor and material required to make the directed splices.

8.5 Pile Points. If pile points are required, as directed by the Con-tracting Officer, payment will be made at the rate of $150 per pile point.

This price shall include all costs incidental to furnishing and properly in-stalling the pile points on the pile.

APPENDIX D

PILE CAPACITY COMPUTATIONS

D-1. General. After the shear strength and stratification has been selected, the capacity of piles may be computed. The geotechnical engineer computes the capacity of a single pile placed in the subgrade at various levels, then fur-nishes to the structural engineer a curve relating the pile tip elevation to the axial capacity. These computations may be for any number of pile types, i.e., timber, concrete, steel H-pile, etc., and the computations should be both in the construction shear strength case Q and the long-term shear strength case S. Therefore, two curves for each compression and tension loading will be produced and the designer should use the lowest composite in selecting an allowable load.

D-2. Example Computations. Included are examples for soil profiles con-sisting of soft clay, sand, silt, and alternating layers. To reduce the number of computations, a timber pile at a single tip elevation is shown.

These computations must be made at each change in soil property and at a close enough interval to describe the curve mentioned in Paragraph D-1. In the examples, each of the various tip elevations used a timber pile having a

12-inch butt diameter and a 7-inch tip diameter, with the butt driven flush to the ground surface.

a. Uniform Clay Profile. This example was developed for a bottom of slab elevation of +10.0 feet.* Using the shear strengths from the laboratory testing, two shear strength trends are developed. The example trend is shown

a. Uniform Clay Profile. This example was developed for a bottom of slab elevation of +10.0 feet.* Using the shear strengths from the laboratory testing, two shear strength trends are developed. The example trend is shown